North Korea test-fired a new ballistic missile carrying a super-large warhead and an improved strategic cruise missile, state media reported Thursday, as leader Kim Jong Un called for increased weapons development.

"If North Korea attempts to use nuclear weapons, it will face the resolute and overwhelming response of our military and the (South Korea)-US alliance," President Yoon Suk Yeol said.

A former defector, unhappy with life in the South, stole a 25-seat shuttle bus this week and attempted to cross a bridge into North Korea before he was apprehended by guards.

North Korea launched several ballistic missiles into the East Sea on Wednesday, South Korea's military said, the isolated regime's second launch in less than a week as tensions ramp up on the Korean Peninsula.

On Tuesday, South Korea publicly showcased its most powerful weapon, the Hyunmoo-5 missile, to mark Armed Forces Day for the first time ever. The exhibition, held at a military airfield in Seongnam, south of Seoul,

Eager citizens waved flags and aged veterans stood at attention as armor rumbled through central Seoul’s concrete canyons, while a line of Apache attack helicopters whirled overhead and formations of fighter jets thundered through the clouds.